Liquid jet apparatus and methods for dental treatments

ABSTRACT

Systems and methods for using a liquid jet apparatus for dental treatments are disclosed. In one implementation, the liquid jet apparatus may include a handpiece configured to deliver a high velocity liquid jet to a desired location in the mouth of a patient. The handpiece may include a positioning member having a channel through or along which the jet can propagate. The positioning member may have a distal end portion configured to be at least partially disposed in a pulp cavity, canal space, or opening in the tooth under treatment. During operation, the jet may impact an impingement surface of the distal end portion of the positioning member and be deflected as a spray through one or more openings in the distal end portion. The liquid jet apparatus may be used for root canal treatments.

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND Field

The present disclosure generally relates to methods and apparatus fortreatment of a tooth and, more particularly, methods and apparatus usingliquid jets for removing organic matter from a tooth.

Description of the Related Art

In conventional root canal procedures, an opening is drilled through thecrown of a diseased tooth, and endodontic files are inserted into theroot canal system to open the canal spaces and remove organic materialtherein. The root canal is then filled with solid matter such as guttapercha or a flowable obturation material, and the tooth is restored.However, this procedure will not remove all organic material from thecanal spaces, which can lead to post-procedure complications such asinfection. In addition, motion of the endodontic file may force organicmaterial through an apical opening into periapical tissues. In somecases, an end of the endodontic file itself may pass through the apicalopening. Such events may result in trauma to the soft tissue near theapical opening and lead to post-procedure complications.

SUMMARY

Various non-limiting aspects of the present disclosure will now beprovided to illustrate features of the disclosed apparatus and methods.

In one aspect, a dental instrument comprises a positioning member havinga channel configured to deliver a high-velocity liquid jet to a cavityin a tooth. The positioning member may have a proximal end portion and adistal end portion. The distal end portion may be configured to directthe liquid jet into the cavity in the tooth. In one embodiment, thepositioning member may comprise an elongated member such as, e.g., aguide tube.

In another aspect, the dental instrument may include a backflowrestrictor that is configured to be applied to the tooth. The backflowrestrictor may be configured to inhibit backflow of fluid out of anopening in the tooth during operation of the liquid jet. At least aportion of the backflow restrictor may be disposed between the proximalend portion and the distal end portion of the positioning member.

In another aspect, a method for treatment of a root canal of a tooth isdescribed. The method comprises disposing an impingement member havingan impingement surface, separate from a tooth, in a cavity in the tooth.The method also comprises generating a high-velocity, coherent,collimated liquid jet, and directing the jet through air toward thecavity such that liquid enters the cavity in the tooth and fills atleast a substantial portion of the cavity. The method also comprisesimpacting the jet on the impingement surface, and passing the jetthrough at least a portion of the liquid filling the at least asubstantial portion of the cavity prior to the impacting.

In another aspect, a method for treatment of a root canal in a tooth isdisclosed. The method comprises generating a high-velocity liquid beamwith a nozzle disposed in an interior of a tooth, and impacting animpingement surface disposed in a fluid environment located in theinterior of the tooth with the high-velocity liquid beam.

For purposes of this summary, certain aspects, advantages, and novelfeatures of the inventions are summarized. It is to be understood thatnot necessarily all such advantages may be achieved in accordance withany particular embodiment of the invention. Thus, for example, thoseskilled in the art will recognize that the inventions disclosed hereinmay be embodied or carried out in a manner that achieves one advantageor group of advantages as taught herein without necessarily achievingother advantages as may be taught or suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view schematically illustrating a root canalsystem of a tooth.

FIG. 2 is a block diagram schematically illustrating an embodiment of asystem adapted to produce a high-velocity liquid jet.

FIG. 3 is a side view schematically illustrating an embodiment of ahandpiece comprising an embodiment of a guide tube for delivery of theliquid jet to a portion of a tooth.

FIGS. 4 and 4A are cross-section views schematically illustratinganother embodiment of a handpiece that can be used to deliver thehigh-velocity liquid jet.

FIGS. 5A and 5B are cross-section views that schematically illustrateembodiments of a nozzle having an orifice.

FIG. 6 is a side view schematically illustrating the distal end of anembodiment of a handpiece comprising an embodiment of a guide tube.

FIGS. 7A-7B are side views schematically illustrating embodiments of thedistal ends of handpieces comprising embodiments of guide tubes.

FIGS. 8A-8C are side views that schematically illustrate additionalembodiments of guide tubes.

FIGS. 9A-9D are cross-section views that schematically illustratevarious embodiments of handpieces, guide tubes, and nozzle locations.

FIGS. 10A-10F are cross-section views schematically illustratingembodiments of guide tubes.

FIGS. 11A-11D are cross-section views schematically illustratingadditional embodiments of guide tubes.

FIGS. 12A-12E include perspective views (left-hand panel) and side views(right-hand panel) schematically illustrating embodiments of theimpingement member.

FIGS. 13A-13E include perspective views (left-hand panel) and side views(right-hand panel) schematically illustrating additional embodiments ofthe impingement member.

FIGS. 14A and 14B are a perspective view (FIG. 14A) and a top view (FIG.14B) schematically illustrating an embodiment of an impingement membercomprising blades that may assist forming a vortex flow in fluid in atooth during treatment.

FIGS. 15A-15C are side views of embodiments of impingement members thatinclude flexible portions to assist inducing circulation into the fluidin the tooth during treatment.

FIGS. 16A and 16B are side views that schematically illustrate furtherembodiments of the guide tube that may assist in forming a variablefluid circulation near the distal end of the guide tube.

FIGS. 17A-17D schematically illustrate embodiments of an impingementmember comprising a material at least partially permeable to the liquidjet. FIG. 17A is a side view along the line A-A shown in FIG. 17B. FIG.17C is a side view along the line C-C shown in FIG. 17D.

FIG. 18 is a perspective view schematically illustrating an embodimentof a guide tube comprising posts disposed near the distal end of theguide tube.

FIGS. 19A-19E each include a perspective view (upper figure) and across-section view (lower figure) taken along the line 19-19 of theupper figure schematically illustrating an embodiment of a guide tube.

FIGS. 20A-20E are top views schematically illustrating examples ofdistributions of the spray that can be produced by various embodimentsof guide tubes comprising posts and/or openings.

FIGS. 21A-21C are side views schematically illustrating embodiments ofguide tubes having curved or angled impingement members.

FIGS. 22A-22C are cross-section views schematically illustratingembodiments of handpieces in which nozzle is not oriented perpendicularto the axis of the guide tube.

FIG. 23 schematically illustrates an embodiment of a handpiececomprising a liquid flow tube configured to provide a stream of liquidto a tooth location.

FIGS. 24A-24F are cross-section views schematically illustratingembodiments of guide tubes.

FIG. 25 schematically illustrates use of a handpiece during a dentaltreatment.

Throughout the drawings, reference numbers may be re-used to indicate ageneral correspondence between referenced elements. The drawings areprovided to illustrate example embodiments described herein and are notintended to limit the scope of the disclosure.

DETAILED DESCRIPTION Overview

The present disclosure describes apparatus and methods for performingdental procedures such as, e.g., endodontic procedures. The disclosedapparatus and methods advantageously may be used with root canalcleaning treatments, for example, to efficiently remove organic and/orinorganic matter from a root canal system. The apparatus and methods maybe used for other dental treatments such as, e.g., tooth cleaning,treatment of dental caries, removal of calculus and plaque, etc. Organicmaterial (or organic matter) includes organic substances typically foundin healthy or diseased teeth or root canal systems such as, for example,soft tissue, pulp, blood vessels, nerves, connective tissue, cellularmatter, pus, and microorganisms, whether living, inflamed, infected,diseased, necrotic, or decomposed. Inorganic matter includes calcifiedtissue and calcified structures, which are frequently present in theroot canal system.

In some embodiments, the disclosed apparatus and methods utilize ahigh-velocity collimated beam of liquid to clean the root canal system,to clean tooth surfaces (e.g., to treat dental caries), etc. Thehigh-velocity liquid beam may generate a pressure wave that canpropagate through the tooth and root canal system and can detach ordissolve organic and/or inorganic material from dentinal surfaces and/ordissociate pulpal tissue. The liquid beam and/or the pressure wave maycause or increase the efficacy of various effects that may occur in thetooth including, but not limited to, acoustic cavitation (e.g., bubbleformation and collapse, microjet formation), fluid agitation, fluidcirculation, sonoporation, sonochemistry, and so forth.

For example, in one aspect of the disclosure, an apparatus for removingorganic and/or inorganic material from a tooth comprises a pressure wavegenerator configured to provide acoustic energy to a tooth. The acousticenergy may be sufficient to cause organic and/or inorganic material inthe tooth to be detached from surrounding dentin. It is believed(although not required) that the effects caused (or enhanced) by theacoustic energy may lead to a cleaning action that delaminates ordetaches the pulpal tissue from the root canal wall, dentinal surfaces,and/or tubules, and may further break such tissue down into smallerpieces.

In some implementations, the pressure wave generator comprisesembodiments of the apparatus described herein. For example, the pressurewave generator may comprise a positioning member (e.g., a guide tube)having a channel or lumen along which or through which a liquid jet canpropagate. The distal end portion of the positioning member may includean impingement surface on which the liquid jet impinges and is deflectedinto jets or spray. The distal end portion of the positioning member mayinclude one or more openings that permit the deflected liquid to exitthe positioning member and interact with the surrounding environment inthe tooth. In some treatment methods, the openings disposed at or nearthe distal end portion of the positioning member are submerged in liquidin the tooth. Without subscribing to or being limited by any particulartheory or mode of operation, the flow of the submerged portion of theliquid jet may generate a cavitation cloud within the treatment fluid.The creation and collapse of the cavitation cloud and/or the jetimpacting the impingement surface may, in some cases, generate asubstantial hydroacoustic field in the tooth. This acoustic field maygenerate pressure waves, oscillations, and/or vibrations in or near thecanal spaces of the tooth and/or interior dentinal surfaces, which arefilled with dentinal tubules. Further cavitation effects may bepossible, including growth, oscillation, and collapse of cavitationbubbles formed in or near the tubules (e.g., possibly at the highsurface-energy sites of the tubules). These (and/or other) effects maylead to efficient cleaning of the pulp cavity of the tooth. In someimplementations, the pressure wave generator may be coupled to ahandpiece or portable jet housing that may be maneuvered in the mouth ofthe patient so as to position or orient the pressure wave generatorrelative to a desired tooth under treatment.

Example Embodiments of Apparatus and Methods for Dental Treatments

FIG. 1 is a cross section schematically illustrating a typical humantooth 10, which comprises a crown 12 extending above the gum tissue 14and at least one root 16 set into a socket (alveolus) within the jawbone 18. Although the tooth 10 schematically depicted in FIG. 1 is amolar, the apparatus and methods described herein may be used on anytype of tooth such as an incisor, a canine, a bicuspid, or a molar. Thehard tissue of the tooth 10 includes dentin 20 which provides theprimary structure of the tooth 10, a very hard enamel layer 22 whichcovers the crown 12 to a cementoenamel junction 15 near the gum 14, andcementum 24 which covers the dentin 20 of the tooth 10 below thecementoenamel junction 15.

A pulp cavity 26 is defined within the dentin 20. The pulp cavity 26comprises a pulp chamber 28 in the crown 11 and a root canal space 30extending toward an apex 32 of each root 16. The pulp cavity 26 containsdental pulp, which is a soft, vascular tissue comprising nerves, bloodvessels, connective tissue, odontoblasts, and other tissue and cellularcomponents. The pulp provides innervation and sustenance to the tooththrough the epithelial lining of the pulp chamber 26 and the root canalspace 30. Blood vessels and nerves enter/exit the root canal space 30through a tiny opening, the apical foramen 32, near a tip of the apex 32of the root 16.

FIG. 2 is a block diagram that schematically illustrates an embodimentof a system 38 adapted to generate a high-velocity jet 60 of fluid foruse in dental procedures. The system 38 comprises a motor 40, a fluidsource 44, a pump 46, a pressure sensor 48, a controller 51, a userinterface 53, and a handpiece 50 that can be operated by a dentalpractitioner to direct the jet 60 toward desired locations in apatient's mouth. The pump 46 can pressurize fluid received from thefluid source 44. The pump 46 may comprise a piston pump in which thepiston is actuatable by the motor 40. The high-pressure liquid from thepump 46 can be fed to the pressure sensor 48 and then to the handpiece50, for example, by a length of high-pressure tubing 49. The pressuresensor 48 may be used to sense the pressure of the liquid andcommunicate pressure information to the controller 51. The controller 51can use the pressure information to make adjustments to the motor 40and/or the pump 46 to provide a target pressure for the fluid deliveredto the handpiece 50. For example, in embodiments in which the pump 46comprises a piston pump, the controller 51 may signal the motor 40 todrive the piston more rapidly or more slowly, depending on the pressureinformation from the pressure sensor 48. In some embodiments, thepressure of the liquid that can be delivered to the handpiece 50 can beadjusted within a range from about 500 psi to about 50,000 psi (1 psi is1 pound per square inch and is about 6895 Pascals (Pa)). In certainembodiments, it has been found that a pressure range from about 2,000psi to about 15,000 psi produces jets that are particularly effectivefor endodontic treatments. In some embodiments, the pressure is about10,000 psi.

The fluid source 44 may comprise a fluid container (e.g., an intravenousbag) holding sterile water, a medical-grade saline solution, anantiseptic or antibiotic solution (e.g., a bleach such as sodiumhypochlorite), a solution with chemicals or medications, or anycombination thereof. More than one fluid source may be used. In certainembodiments, it is advantageous for jet formation if the liquid providedby the fluid source 44 is substantially free of dissolved gases (e.g.,less than about 0.1% by volume, less than about 1 mg of gas per liter ofsolution, or less than some other value), which may reduce the acousticeffects of cavitation. In some embodiments, the fluid source 44comprises degassed distilled water. A bubble detector (not shown) may bedisposed between the fluid source 44 and the pump 46 to detect bubblesin the liquid and/or to determine whether liquid flow from the fluidsource 44 has been interrupted or the container has emptied. The liquidin the fluid source 44 may be at room temperature or may be heatedand/or cooled to a different temperature. For example, in someembodiments, the liquid in the fluid source 44 can be chilled to reducethe temperature of the high velocity jet generated by the system 38,which may reduce or control the temperature of the fluid inside a tooth.In some treatment methods, the liquid in the fluid source 44 can beheated, which may increase the rate of chemical reactions that may occurin the tooth during treatment.

The handpiece 50 can be configured to receive the high pressure liquidand can be adapted at a distal end to generate a high-velocity beam orjet 60 of liquid for use in dental procedures. In some embodiments, thesystem 38 may produce a coherent, collimated jet of liquid (furtherdescribed below). The handpiece 50 may be sized and shaped to bemaneuverable in the mouth of a patient so that the jet 60 may bedirected toward or away from various portions of the tooth 10. In someembodiments, the handpiece comprises a housing or cap that can becoupled to the tooth 10.

The controller 51 may comprise a microprocessor, a special or generalpurpose computer, a floating point gate array, and/or a programmablelogic device. The controller 51 may be used to control safety of thesystem 38, for example, by limiting system pressures to be below safetythresholds and/or by limiting the time that the jet 60 is permitted toflow from the handpiece 50. The system 38 may also include a userinterface 53 that outputs relevant system data or accepts user input(e.g., a target pressure). In some embodiments, the user interface 53comprises a touch screen graphics display. In some embodiments, the userinterface 53 may include controls for a dental practitioner to operatethe liquid jet apparatus. For example, the controls can include a footswitch to actuate or deactuate the jet.

The system 38 may include additional and/or different components and maybe configured differently than shown in FIG. 2. For example, the system38 may include an aspiration pump that is coupled to the handpiece 50(or an aspiration cannula) to permit aspiration of organic matter fromthe mouth or tooth 10. In other embodiments, the system 38 may compriseother pneumatic and/or hydraulic systems adapted to generate thehigh-velocity beam or jet 60. Also, certain embodiments of the system 38may utilize or be configured similarly to embodiments of the apparatusand systems described in U.S. Pat. No. 6,224,378, issued May 1, 2001,entitled “METHOD AND APPARATUS FOR DENTAL TREATMENT USING HIGH PRESSURELIQUID JET,” U.S. Pat. No. 6,497,572, issued Dec. 24, 2002, entitled“APPARATUS FOR DENTAL TREATMENT USING HIGH PRESSURE LIQUID JET,” U.S.Patent Publication No. 2007/0248932, published Oct. 25, 2007, entitled“APPARATUS AND METHODS FOR TREATING ROOT CANALS OF TEETH,” and/or U.S.Patent Publication No. 2010/0143861, published Jun. 10, 2010, entitled“APPARATUS AND METHODS FOR MONITORING A TOOTH,” the entire disclosure ofeach of which is hereby incorporated by reference herein for all that itteaches or discloses.

In certain embodiments, the system 38 may be configured to produce aliquid jet 60 that forms a substantially parallel beam (e.g., is“collimated”) over distances ranging from about 0.01 cm to about 10 cm.In some embodiments, the velocity profile transverse to the propagationaxis of the jet is substantially constant (e.g., is “coherent”). Forexample, in some implementations, away from narrow boundary layers nearthe outer surface of the jet 60 (if any), the jet velocity issubstantially constant across the width of the jet. Therefore, incertain advantageous embodiments, the liquid jet 60 delivered by thedental handpiece 50 may comprise a coherent, collimated jet (a “CCjet”). In some implementations, the CC jet may have velocities in arange from about 100 m/s to about 300 m/s, for example, about 190 m/s insome embodiments. In some implementations, the CC jet can have adiameter in a range from about 5 microns to about 1000 microns, in arange from about 10 microns to about 100 microns, in a range from about100 microns to about 500 microns, or in a range from about 500 micronsto about 1000 microns. Further details with respect to CC jets that canbe produced by embodiments of the system and apparatus described hereincan be found in U.S. Patent Publication No. 2007/0248932, which ishereby incorporated by reference herein in its entirety for all that itdiscloses or teaches.

FIG. 3 is a side view schematically illustrating an embodiment of ahandpiece 50 comprising an embodiment of a positioning member configuredto deliver the liquid jet 60 to a portion of the tooth 10. In variousembodiments, the positioning member comprises a guide tube 100.Embodiments of the handpiece 50 can be used with any of the embodimentsof the guide tubes 100 described herein. The handpiece 50 comprises anelongated tubular barrel 52 having a proximal end 56 that is adapted toengage tubing 49 from the system 38. The barrel 52 may include featuresor textures 55 that enhance grasping the handpiece 50 with the fingersand thumb of the operator. The handpiece 50 can be configured to behandheld. In some cases, the handpiece 50 can be configured to beportable, movable, orientable, or maneuverable with respect to thepatient. In some implementations, the handpiece 50 can be configured tobe coupled to a positioning device (e.g., a maneuverable or adjustablearm).

The handpiece 50 can be shaped or sized differently than shown in FIG. 3(or other figures herein). For example, the handpiece 50 can comprise ahousing or cap that can be coupled to the tooth 10. In some suchimplementations, the elongated tubular barrel 52 may not be used, and adental practitioner maneuvers the housing into a desired location in thepatient's mouth.

Optionally, a flow restrictor 210 can be disposed at the distal end 58of the handpiece 50. In the illustrated embodiment, the flow restrictor210 substantially surrounds the guide tube 100. As will be furtherdescribed with reference to FIG. 25, the flow restrictor 210 may beconfigured to contact a portion of the tooth 10 during a dentaltreatment and may restrict, inhibit, or reduce backflow of fluid out ofthe tooth during treatment.

FIGS. 4 and 4A are cross-section views that schematically illustrateanother embodiment of a handpiece 50 adapted for delivering thehigh-velocity jet 60. The handpiece 50 has a central passageway 54extending axially therethrough and at the proximal end 56 is adapted toengage the tubing 49 from the system 38 in order for the passageway 54to be in fluid communication with the high pressure liquid delivered bythe system 38. A distal end 58 of the barrel 52 (shown in close-up inFIG. 4A) includes a threaded recess adapted to engage complementarythreads of a nozzle mount 62, which is configured to hold a nozzle 64.The nozzle mount 62 may be tightly screwed into the distal end 58 of thebarrel 52 to secure the nozzle 64 adjacent to a distal end of thepassageway 52. As will be described with reference to FIGS. 11A-11C, thenozzle 64 can be disposed in different locations in other embodiments ofthe handpiece.

FIG. 4A schematically illustrates an embodiment of a guide tube 100secured to the nozzle mount 62. In some embodiments, the guide tube 100can be formed integrally with the nozzle mount 62. In other embodiments,the guide tube 100 can be secured to the nozzle mount 62 via welding(e.g., laser welding), adhesives, fasteners, etc. Embodiments of theguide tube 100 can be manufactured using a variety of process including,e.g., metal injection molding, laser cutting or welding, micro welding,etc. Various embodiments of the guide tube 100 will be further describedbelow. In some implementations, the handpiece 50 may be configured todeliver two or more jets, and in some such embodiments, two or morenozzles 62 and/or guide tubes 100 may be disposed at the distal end 58of the handpiece 50.

The nozzle 64 can comprise a circular, disc-like element having anorifice 66 formed therein. The nozzle 64 may be fabricated from asuitably rigid material that resists deformation under high pressuresuch as, for example, metal, ceramic, or synthetic sapphire or ruby.Embodiments of the nozzle 64 can be manufactured by a variety ofprocesses including, e.g., electroforming (including nickel-cobaltelectroforms), micro-plunge electrical discharge machining (EDM), lasercutting, etc.

In the illustrated embodiment, the nozzle mount 62 secures the nozzle 64substantially perpendicular to the passageway 54 so that high pressureliquid in the passageway 54 can flow through the orifice 66 and emergeas a highly collimated beam of fluid traveling along a longitudinal jetaxis 80 that is substantially coaxial with the barrel 52 of thehandpiece 50. The orifice 66 may have any desired shape such as, e.g.,circular, oval, rectangular, polygonal, etc. The orifice 66 may, butneed not be, substantially centered in the nozzle 64. In someembodiments, the nozzle 64 may have two or more orifices 66, with eachorifice configured to emit a liquid jet. In some embodiments, the distalend 58 of the handpiece 50 may include additional components, forexample, to assist guiding or directing the jet 60 and/or to provideaspiration.

Various aspects of the nozzle 64 (e.g., surface finish of the orifice)may be selected to provide desired fluid flow or jet properties. Forexample, in various embodiments, the liquid jet emitted from the orifice66 can be a CC jet, a jet with a perturbed surface, or a spray of fluid(as measured in air). Without subscribing to or requiring any particulartheory or mode of operation, it is believed that a nozzle 64 configuredto produce a CC jet may create a higher power acoustic field (e.g.,pressure waves) in a tooth (e.g., in dentin or in liquid in the pulpcavity) than a nozzle 64 that is configured not to produce a CC jet. Forexample, it is believed that a CC-Jet may create a large velocitygradient that may result in a large pressure gradient that may causestronger cavitation, which may cause a higher power acoustic field.Therefore, in some treatment methods, a system configured to produce aCC jet may be used for root canal cleaning, and in other treatmentmethods, system configured to produce a non-CC jet may be used for toothcleaning (e.g., caries treatment, removal of calculus and plaque,superficial cleaning, etc.).

Different types of fluid streams (e.g., a jet or a spray) can begenerated by the nozzle 64 and/or orifice 66 based at least in part onflow parameters, nozzle geometry, surface quality of the orifice 66 (orother surfaces in the nozzle 64), and so forth. FIGS. 5A and 5B arecross-section views that schematically illustrate embodiments of anozzle 64 having an orifice 66. Nozzles and/or orifices can beconfigured in a number of ways to provide a CC jet. For example, asschematically illustrated in FIG. 5A, in some embodiments a relativelysharp-edged, cone-down orifice 66 can be used. In other embodiments,other shapes can be used, e.g., conical orifices, capillary orifices,cone-capillary orifices, etc. Arrow 72 shows the direction of fluid flowthrough the orifice 66 during operation of the liquid jet apparatus.

In the illustrated embodiments, the orifice 66 is substantiallycircularly symmetric, although this is not a requirement. The orifice 66may, but need not, be formed at an angle to a proximal surface 70 a ofthe nozzle 64. The angle may be about 0 degrees (e.g., the orifice issubstantially perpendicular to the proximal surface 70 a), about 10degrees, about 20 degrees, about 30 degrees, about 40 degrees, about 50degrees, about 60 degrees, or some other angle. The orifice 66 shown inFIGS. 5A and 5B comprises a proximal portion 68 a that can besubstantially cylindrical with a length L₁ and a diameter D₁. Theorifice 66 can comprise a distal portion 68 b that can be substantiallyconical with a cone angle α and can have a length L₂ and a diameter D₂.As schematically illustrated in FIG. 5B, the cone angle α can be about180 degrees, so that the distal portion 68 b is substantiallycylindrical. The diameter D₂ can, but need not be, different from thediameter D₁. For example, in various embodiments, D₂ can beapproximately the same as D₁, D₂ can be larger than D₁, or D₂ can besmaller than D₁. The length L₂ can, but need not be, different from thelength L₁. For example, in various embodiments, L₂ can be approximatelythe same as L₁, L₂ can be larger than L₁, or L₂ can be smaller than L₁.The orifice geometry schematically illustrated in FIGS. 5A and 5B maycause a relatively abrupt change in velocity of the liquid flowingthrough the orifice 66.

For length-to-diameter ratios L₁/D₁ in a range from about 0 to about0.7, the flow may be constricted, may not reattach to the walls of theorifice, and may form a CC-Jet with a relatively long break-up length.For length-to-diameter ratios L₁/D₁ in a range from about 0.7 to about4, cavitation may be induced. Initially, the flow out of the nozzle 64may reattach to the walls of the orifice 66, and the fluid stream maynot be a CC jet. For sufficiently high pressures (near the inlet 74 tothe nozzle 64), cavitation may occur near the inlet 74. The cavitationregion can grow and may form an air entrainment region sufficientlylarge to induce air from downstream to flow up to the nozzle's outlet 76and separate liquid from the walls of the orifice 66, which may helpcreate a CC jet. In other embodiments, length-to-diameter ratios L₁/D₁above 4 can be used.

A possible advantage of using length-to-diameter ratios L₁/D₁ in therange from about 0 to about 0.7 is that cavitation, which may causedamage to the nozzle, may not occur. A possible disadvantage is that asufficiently hard material able to withstand relatively high pressuremay be used for the nozzle 64. A possible advantage of usinglength-to-diameter ratios L₁/D₁ in the range from about 0.7 to about 4is that the larger L₁/D₁ ratio allows the nozzle's geometry to beadapted for a wider range of materials. A possible disadvantage ofhigher L₁/D₁ ratios is that cavitation may cause damage to the nozzle 64and lead to a shorter working life for the nozzle.

It is believed, although not required, that for L₁/D₁ ratios at least inthe range from about 0 to about 4, the nozzle design may be relativelyinsensitive to the cone angle α. Accordingly, cone angles near about 0degrees can be used (e.g., the orifice 64 is approximately a cylinderover the length L₁ and L₂). In this case, the orifice 66 may be thoughtof as comprising just the proximal portion 68 a and not the distalportion 68 b. In other embodiments, only the distal portion 68 b isused, and the orifice 66 is substantially conical. Many possibleconfigurations of the orifice 66 can be used, and the examples in FIGS.5A and 5B are intended to be illustrative and not to be limiting.

For example, as schematically illustrated in FIG. 5B, cone angles ofabout 180 degrees can be used. In this example, both the proximalportion 68 a and the distal portion 68 b are substantially cylindrical,with the diameter D₂ of the distal portion 68 b larger than the diameterD₁ of the proximal portion 68 a. In other embodiments, the diameter D₂of the distal portion 68 b may be smaller than the diameter D₁ of theproximal portion 68 a. Shaping the proximal portion 68 a or the distalportion 68 b substantially as cylinders may advantageously makemanufacturing the orifice simpler. In other embodiments, cone angles ina range from about 0 degrees to about 20 degrees, about 20 degrees toabout 45 degrees, about 45 degrees to about 90 degrees, about 90 degreesto about 120 degrees, or some other range can be used.

In various embodiments of the nozzle 64, the orifice 66 may have adiameter D₁ at the inlet 74 or a diameter D₂ at the outlet 76 that maybe in a range from about 5 microns to about 1000 microns. Other diameterranges are possible. In various embodiments, one or both of thediameters D₁ or D₂ may be in a range from about 10 microns to about 100microns, a range from about 100 microns to about 500 microns, or rangefrom about 500 microns to about 1000 microns. In various otherembodiments, one or both of the orifice diameters D₁ or D₂ may be in arange of about 40-80 microns, a range of about 45-70 microns, or a rangeof about 45-65 microns. In one embodiment, the orifice diameter D₁ isabout 60 microns. The ratio of axial length L₁ to diameter D₁, the ratioof axial length L₂ to diameter D₂, or the ratio of total axial lengthL₁+L₂ to diameter D₁, D₂, or average diameter (D₁+D₂)/2 may, in variousembodiments, be about 50:1, about 20:1, about 10:1, about 5:1, about1:1, or less. In one embodiment, the axial length L₁ is about 500microns. In some cases, the axial length L₂ (or the ratio L₂/D₂) can beselected so that the flow through the orifice 66 does not reattach tosurface 70 c. The axial length L₂, the diameter D₂, or other parametersshown in FIGS. 5A and 5B may be selected so that the nozzle 64 hassufficient structural rigidity to withstand load from pressurized fluid.

With reference to the example nozzle 64 schematically illustrated inFIG. 5A, the curvature of corner or edge 69 is denoted by r, and thesurface roughness of surfaces 70 a, 70 b, and 70 c is denoted by Ra.Relatively abrupt geometry changes in the nozzle 64 may induce arelatively large velocity change, which may lead to a relativelyconstricted jet. For example, the ratio of surface roughness Ra toorifice diameter D₁, Ra/D₁, for some or all of the surfaces 70 a-70 cmay be less than about 0.01, less than about 0.005, or less than about0.001 in various embodiments. The ratio of corner curvature radius r toorifice diameter D₁, r/D₁, may be less than about 0.1, less than about0.05, less than about 0.04, less than about 0.02, or less than about0.01 in various embodiments. The surface roughness Ra of the surfaces 70a, 70 b, or 70 c can have a root-mean-square (rms) surface roughnessless than about 10 microns, less than about 1 micron, or less than about0.1 microns.

In certain embodiments, the nozzle 64 (or surface portions adjacent theliquid) can be formed from a hydrophobic material. In certain suchembodiments, the contact angle (e.g., the angle formed between a solidsurface and a liquid) of the hydrophobic material may be smaller thanabout π/2 radians. In some implementations, the nozzle 64 may comprisestainless steel or a plastic such as, e.g., acrylic. Other materials maybe used such as, e.g., aluminum, copper, or polycarbonate, but in somecases, nozzles formed from such materials may not produce asubstantially constricted jet.

FIG. 6 is a side view schematically illustrating the distal end 58 of anembodiment of a handpiece 50 comprising an embodiment of a guide tube100. FIGS. 7A-7B are side views schematically illustrating alternativeembodiments of the distal ends 58 of handpieces 100 comprisingembodiments of guide tubes 100. In the illustrated embodiments, theguide tube 100 comprises a substantially straight, elongated,cylindrical tube. In other embodiments, the guide tube 100 may have adifferent shape (e.g., curved) or a different cross-section (see, e.g.,FIGS. 10A-10F below). In some embodiments, the guide tube 100 comprisesa plurality of tubes that may at least partially disposed in, on, oraround each other (e.g., to form a “telescoping” configuration). Forexample, the guide tube 100 may comprise at least a first tube and asecond tube configured such that the proximal end of the second tube isdisposed in the distal end of the first tube (see, e.g., an exampleshown in FIG. 22A).

With reference to FIG. 6, the guide tube 100 has a proximal end 102 thatcan be attached or disposed adjacent the distal end 58 of the handpiece50 and a distal end 104 that, during treatment, can be disposed in,near, or on a portion of the tooth 10 under treatment. For example, thedistal end 104 of the guide tube 100 can be disposed in a cavity in thetooth 10. The cavity may include natural or artificial spaces, openings,or chambers in the tooth such as, e.g., the pulp chamber 28, a canalspace 30, an opening drilled or formed in the tooth by a dentalpractitioner, etc. The guide tube 100 has a channel 84 that permitspropagation of the liquid jet 60 along at least a portion of the lengthof the guide tube 100. For example, the liquid jet 60 may propagatealong the longitudinal jet axis 80. In the embodiments schematicallydepicted in FIGS. 6 and 7A-7B, the longitudinal jet axis 80 issubstantially collinear with the longitudinal axis of the channel 84 andthe guide tube 100. In other embodiments, the longitudinal jet axis 80may be offset from the longitudinal axis of the channel 84 and/or theguide tube 100, for example, by offsetting the orifice 66 of the nozzle64 from relative to the axes of the channel 84 and/or guide tube 100.

In various embodiments of the guide tube 100, the cross-section of thechannel 84 can be substantially closed (e.g., a lumen) (see, e.g., FIGS.10A-10F described below). In other embodiments, the cross-section of thechannel 84 can be partially open at least along a portion of the lengthof the guide tube 100. For example, the cross-section of the channel 84may have a generally C-shape or U-shape. A possible advantage of certainembodiments of guide tubes 100 comprising a substantially closed channel84 is that the jet is protected from disruption by elements outside thechannel 84 as the jet propagates through the guide tube 100. Also, useof a substantially closed channel 84 may reduce the likelihood of airentering the pulp chamber 26 during treatment.

The proximal end 102 of the guide tube 100 can be attached to the distalend 58 of the dental handpiece 50. The liquid jet 60 (which may be a CCjet) can propagate from the handpiece 50 along the jet axis 80, whichcan pass through the channel 84 of the guide tube 100. It isadvantageous, in some embodiments, if the guide tube 100 is positionedand/or oriented on the handpiece 50 so that the jet axis 80 is alignedsubstantially parallel to the longitudinal axis of the channel 84 of theguide tube 100 in order that the liquid jet 60 propagates along thechannel and does not impact a wall of the guide tube (except as furtherdescribed below). In some embodiments, the jet axis 80 may be offsetfrom the longitudinal axis of the channel 84 or the guide tube 100.

Embodiments of the guide tube 100 can be sized or shaped such that thedistal end 104 can be positioned through an endodontic access openingformed in the tooth 10, for example, on an occlusal surface, a buccalsurface, or a lingual surface. For example, the distal end 104 of theguide tube may be sized or shaped so that the distal end 104 can bepositioned in the pulp cavity 26 of the tooth 10, e.g., near the pulpalfloor, near openings to the canal space 30, or inside the canalopenings. The size of the distal end 104 of the guide tube 100 can beselected so that the distal end 104 fits through the access opening ofthe tooth 10. In some embodiments, the width of the guide tube 100 canbe approximately the width of a Gates-Glidden drill, for example, a size4 drill. In some embodiments, the guide tube 100 can be sized similarlyto gauge 18, 19, 20, or 21 hypodermic tubes. The width of the guide tube100 may be in a range from about 0.1 mm to about 5 mm, in a range fromabout 0.5 mm to about 1.5 mm, or some other range. The length of theguide tube 100 can be selected so that the distal end 104 of the guidetube 100 can be disposed at a desired location in the mouth. Forexample, the length of the guide tube 100 between the proximal end 102and the distal end 104 may be in a range from about 1 mm to about 50 mm,from about 10 mm to about 25 mm, or in some other range. In someembodiments, the length is about 18 mm, which may allow the distal end104 of the guide tube 100 to reach the vicinity of the pulpal floor in awide range of teeth. For teeth that may not have a pulpal chamber or apulpal floor (e.g., anterior teeth), the distal end 104 of the guidetube 100 can be inserted into the canal space of the tooth 10.

As schematically illustrated in FIGS. 6 and 7A-7B, certain embodimentsof the guide tube 100 can comprise an impingement member 110 (which alsomay be referred to herein as a deflector). The jet 60 can propagatealong the channel 84 and impinge upon the impingement member 110,whereby at least a portion of the jet 60 can be slowed, disrupted ordeflected, which can produce a spray 90 of liquid. The spray 90 maycomprise droplets, beads, mist, jets, or beams of liquid in variousimplementations. Embodiments of the guide tube 100 which include animpingement member 110 may reduce or prevent possible damage that may becaused by the jet during certain dental treatments. For example, use ofthe impingement member 110 may reduce the likelihood that the jet mayundesirably cut tissue or propagate into the root canal spaces 30 (whichmay undesirably pressurize the canal spaces in some cases). The designof the impingement member 110 (further described below) may also enablea degree of control over the fluid circulation or pressure waves thatcan occur in the pulp cavity 26 during treatment.

The impingement member 110 may be disposed in a cavity in the tooth 10.In some methods, the impingement member 110 is disposed in fluid in thetooth 10, and the liquid jet 60 impacts an impingement surface of theimpingement member 110 while the impingement member 110 is disposed inthe cavity. The liquid jet 60 may be generated in air or fluid, and insome cases, a portion of the liquid jet 60 passes through at least some(and possibly a substantial portion) of fluid in the cavity in the tooth10 before impacting the impingement member 110. In some cases, the fluidin the tooth cavity may be relatively static; in other cases, the fluidin the tooth cavity may circulate, be turbulent, or have fluidvelocities that are less than (or substantially less than) the speed ofthe high-velocity liquid jet.

In some implementations, the impingement member 110 is not used, and thejet 60 can exit the guide tube 100 without substantial interference fromportions of the guide tube 100. In some such implementations, afterexiting the guide tube 100, the jet 60 may be directed toward a dentinalsurface, where the jet may impact or impinge upon the dentinal surfaceto provide acoustic energy to the tooth, to superficially clean thetooth, and so forth.

The guide tube 100 can include an opening 120 that permits the spray 90to leave the distal end 104 of the guide tube 100. In some embodiments,multiple openings 120 can be used (see, e.g., FIGS. 18-20E), forexample, two, three, four, five, six, or more openings. The opening 120can have a proximal end 106 and a distal end 108. The distal end 108 ofthe opening 120 can be disposed near the distal end 104 of the guidetube 100. The opening 120 can expose the liquid jet 60 (and/or the spray90) to the surrounding environment, which may include air, liquid,organic material, etc. For example, in some treatment methods, when thedistal end 104 of the guide tube 100 is inserted into the pulp cavity120, the opening 120 permits the material or fluid inside the pulpcavity 26 to interact with the jet 60 or spray 90. A hydroacoustic field(e.g., pressure waves, acoustic energy, etc.) may be established in thetooth 10 (e.g., in the pulp cavity 26, the canal spaces 30, etc.) by theimpingement of the jet 60 on the impingement member 110, interaction ofthe fluid or material in the tooth 10 with the jet 60 or they spray 90,fluid circulation or agitation generated in the pulp cavity 26, or by acombination of these factors (or other factors). The hydroacoustic fieldmay include acoustic power over a relatively broad range of acousticfrequencies (e.g., from about a few kHz to several hundred kHz orhigher). The hydroacoustic field in the tooth may influence, cause, orincrease the strength of effects including, e.g., acoustic cavitation(e.g., bubble formation and collapse, microjet formation), fluidagitation, fluid circulation, sonoporation, sonochemistry, and so forth.It is believed, although not required, that the hydroacoustic field,some or all of the foregoing effects, or a combination thereof may actto disrupt or detach organic material in the tooth, which mayeffectively clean the pulp cavity 26 and/or the canal spaces 30.

The length of the opening 120 between the proximal end 106 and thedistal end 108 is referred to as X (see, e.g., FIG. 6). In variousembodiments, the length X may be in a range from about 0.1 mm toapproximately the overall length of the guide tube 100. For example,FIGS. 6 and 7A-7B show three guide tube embodiments having differentopening lengths. In some embodiments, the length X is in a range fromabout 1 mm to about 10 mm. In some cases, the length X is selected sothat the opening 120 remains submersed by fluid or material in the pulpcavity 26 of the tooth 10 during treatment. A length X of about 3 mm canbe used for a wide variety of teeth. In some embodiments, the length Xis a fraction of the overall length of the guide tube 100. The fractioncan be about 0.1, about 0.25, about 0.5, about 0.75, about 0.9, or adifferent value. In some embodiments, the length X is a multiple of thewidth of the guide tube 100 or the channel 84. The multiple can be about0.5, about 1.0, about 2.0, about 4.0, about 8.0, or a different value.The multiple can be in a range from about 0.5 to about 2.0, about 2.0 toabout 4.0, about 4.0 to about 8.0, or more. In other embodiments, thelength X is a multiple of the width of the jet, e.g., 5 times, 10 times,50 times, or 100 times the width of the jet. The multiple can be in arange from about 5 to about 50, about 50 to about 200, about 200 toabout 1000, or more. In some implementations, the length X of theopening 120 can be selected (at least in part) such that thehydroacoustic field generated in a tooth has desired propertiesincluding, e.g., desired acoustic power in the tooth at one or moreacoustic frequencies.

FIGS. 8A-8C are side views that schematically illustrate additionalembodiments of guide tubes. The embodiments of the guide tubes 100 shownin FIGS. 8A-8C comprise a body 130 that extends from the proximal end102 of the guide tube 100 to the proximal end 106 of the opening 120. Inthe embodiment schematically depicted in FIG. 8A, the body 130 does notinclude any holes and the wall or walls of the body 130 aresubstantially solid. In the embodiments schematically depicted in FIGS.8B and 8C, the body 130 includes one or more holes 124. The holes 124can have any desired shape, arrangement, or placement along the body130. During operation of the jet 60, the relatively high speed of thejet 60 may tend to draw air into the channel 84 of the guide tube 100through any holes 124 (if present and if not submersed in surroundingfluid). The air can travel alongside the jet 60 toward the distal end104 of the guide tube 100. In some treatment methods, the drawn air mayenter the pulp cavity 26, which may, in some cases, may draw air intothe canal spaces 30. Also, the drawn air may, in some cases, diminishthe acoustic power or fluid circulation provided by the jet 60.Therefore, a possible advantage of the guide tube 100 schematicallydepicted in FIG. 8A is that the lack of holes on the body 130 caninhibit or prevent air from being drawn into the guide tube duringtreatment. In some embodiments, holes 124 are used on the guide tube,but the holes 124 are disposed near the proximal end 106 of the opening120 so that during treatment the holes remain submersed in fluid presentin the pulp cavity 26. In other embodiments, holes 124 that may beexposed to air are used on the guide tube 100, and the size of suchholes 124 are sufficiently small not to substantially draw air into theguide tube 100 during treatment with the liquid jet 60. For example,such holes 124 may have sizes less than about 300 μm, less than about700 μm, less than about 1000 μm, or some other size.

FIGS. 4 and 4A schematically illustrate an embodiment of the handpiece50 in which the nozzle 64 is disposed in a nozzle mount 62 near thedistal end 58 of the handpiece 50. In other embodiments, the nozzle 64can be located in other locations in the handpiece 50 or the guide tube50. FIGS. 9A-9D are cross-section views that schematically illustratevarious embodiments of handpieces 50, guide tubes 100, and locations ofnozzles 64. In FIGS. 9A-9D, the handpiece 50 comprises a conduit 57having a passageway 54 through which pressurized liquid delivered by thesystem 38 can flow. In the embodiments of the handpiece 50 shown inFIGS. 9A, 9B, and 9D, an external portion 57 a of the conduit 57 extendsaway from the distal end 58 of the handpiece. The guide tube 100comprises the external portion 57 a of the conduit 57 and (optionally)an end portion 57 b. In the embodiments shown in FIGS. 9A, 9B, and 9D,the end portion 57 b comprises the impingement member 100 and theopening 120. In the embodiments shown in FIGS. 9A, 9B, and 9D, thenozzle 64 is disposed at the distal end of the external conduit 57 a. Inthe example embodiments shown in FIGS. 9A and 9B, the overall length ofthe guide tube 100 is about the same, with the external conduit 57 abeing longer (shorter) and the end portion 57 b being shorter (longer)in FIGS. 9A and 9B, respectively. In other embodiments, the relativelengths of the external conduit 57 a (if any) and the end portion 57 b(if any) may be selected as desired. For example, in some cases, theexternal conduit 57 a may be more rigid than the end portion 57 b (e.g.,because the conduit may have thicker walls), and if increased rigidityis desired, the length of the external conduit 57 a may be longer thanthe length of the end portion 57 b (if any). As another example, inother cases it may be easier to form the opening 120 in the end portion57 b (e.g., because the end portion may have thinner walls), and in somesuch cases, the end portion 57 b may be made relatively longer. In someembodiments, the nozzle 64 can be formed integrally with the conduit 57or 57 a. In some such embodiments, the orifice 66 may be formed at adistal end surface of the conduit 57 or 57 a (e.g., via laser cutting orEDM).

FIG. 9D shows an embodiment of the handpiece 50 in which the guide tube100 comprises a bend 59. In this illustrative example, the bend 59 islocated on the external conduit 57 a. In other embodiments, the bend (oradditional bends) may be located elsewhere along the guide tube 100,e.g., along the end portion 57 b (if used). Guide tubes comprising bendsmay assist a dental practitioner in disposing the distal end 104 of theguide tube 100 in a desired location in the patient's mouth. A guidetube 100 comprising one or more bends may have a shorter profile lengthL_(P) measured perpendicularly from a distal surface 58 a of thehandpiece to the distal end 104 of the guide tube 100 than a straightguide tube 100 having the same overall length (measured along the guidetube). The shorter profile length of some guide tube embodiments mayallow the guide tube to be more easily positioned in the mouth or toreach pulpal cavities. Certain teeth may lack a pulpal floor (e.g.,anterior teeth) or a crown. For such teeth, a relatively short profileguide tube 100 may make delivering the jet 60 or spray 90 to the desiredregion in the tooth easier.

FIG. 9C shows an embodiment of the handpiece 50 in which an externalconduit 57 a is not used. In this embodiment, the proximal end 102 ofthe guide tube 100 is disposed at the bottom 58 a of the distal end 58of the handpiece 50, and the nozzle 64 is disposed near the proximal end102 of the guide tube 100. In other embodiments, the nozzle 64 isdisposed near the distal end of the guide tube 100 (e.g., near theproximal end 106 of the opening 120).

Therefore, in various embodiments, the nozzle 64 can be disposed at aposition upstream of the guide tube 100 (e.g., in the conduit 57 insidethe handpiece 50), at a position at or near the proximal end 102 of theguide tube 100, at a position inside the guide tube 100 between theproximal end 102 of the guide tube 100 and the proximal end 106 of theopening 120, or at a position at or near the proximal end 106 of theopening 120. In some embodiments, guide tube 100 comprises a proximalportion and a distal portion. The nozzle 64 can be disposed in thedistal portion of the guide tube 100 such that the distal portionextends distally beyond the nozzle 64. The distal portion extendingdistally beyond the nozzle 64 may include the impingement member 110. Insome such embodiments, the proximal portion comprises a proximal half ofthe guide tube 100, and the distal portion comprises a distal half ofthe guide tube 100.

FIGS. 10A-10F are cross-section views schematically illustrating variousembodiments of the guide tubes 100. The cross-section of the channel 84and/or the guide tube 100 may be substantially circular (see, e.g.,FIGS. 10A, 10B, 10D), oval (see, e.g., FIG. 10F), rectangular, polygonal(e.g., hexagonal as shown in FIG. 10C for the guide tube and pentagonalas shown in FIG. 10D for the channel), or some other shape. Thecross-sectional shape and/or size of the guide tube 100 and/or thechannel 84 can vary along the longitudinal axis of the guide tube 100.The cross-sectional shape of the channel 84 can be the same as ordifferent from the cross-sectional shape of the guide tube 100 (see,e.g., FIGS. 10C and 10D). In certain embodiments, the cross-sectionalshapes of the channel and the guide tube are substantially circular, andthe channel is substantially concentric with the guide tube (see, e.g.,FIGS. 10A and 10B). The guide tube 100 may comprise one or moreextensions 88, which may run longitudinally along the guide tube 100,which may increase the strength of the tube (see, e.g., FIG. 10E).

In some embodiments, the cross-section of the guide tube 100 is largerat the proximal end 102 than at the distal end 104, which may increasethe rigidity of the guide tube 100. In various embodiments, thecross-section of the channel 84 may change along the longitudinal axis80 of the guide tube (e.g., narrowing toward the distal end 104) or thecross-section of the channel may be substantially constant. Thelongitudinal axis of the channel 84 can, but need not, be substantiallycollinear with the longitudinal axis 80 of the guide tube 100. In someembodiments, the orifice 66 is aligned with the longitudinal axis of thechannel or the guide tube. The surface of the channel 84 may besubstantially smooth, which beneficially may reduce the likelihood ofturbulent air flow interfering with or disrupting the jet. In someembodiments, the surface of the channel 84 can be contoured, curved,spiraled, or twisted.

FIGS. 11A-11C are cross-section views schematically illustratingembodiments of guide tubes 100 capable of propagating multiple jets. Inthe embodiments shown in FIGS. 11A and 11B, the guide tubes 100 comprisemultiple channels. For example, FIG. 11A shows an embodiment of theguide tube 100 having three channels 84 a-84 c. Each of the threechannels 84 a-84 c is capable of propagating a jet along thecorresponding longitudinal jet axes 80 a-80 c. FIG. 11B shows anembodiment of the guide tube 100 having four channels 84 a-84 d. Each ofthe four channels 84 a-84 d is capable of propagating a jet along thecorresponding longitudinal jet axes 80 a-80 d. In other embodiments, adifferent number of channels may be used such as, e.g., two channels,five channels, or more. The guide tubes 100 can have structural elements92 (e.g., baffles) that separate the channels, for example, as shown inFIGS. 11A and 11B. The structural elements 92, if used, may extend alongsubstantially all or only a portion of the length of the guide tube 100.In some embodiments, the structural elements extend from the proximalend 102 of the guide tube 100 to the upper portion of a window in theguide tube (described below).

FIG. 11C schematically illustrates an embodiment of the guide tube 100having a single channel 84 through which multiple jets (e.g., two jetsin this embodiment) can propagate along longitudinal jet axes 80 a and80 b. In other embodiments, the guide tube can be configured so thatthree, four, or more jets can propagate through the channel 84. In theillustrated embodiment, both jet axes 80 a and 80 b are offset from thelongitudinal axis 86 of the channel 84. In other embodiments, one (ormore) of the jet axes could be substantially aligned with thelongitudinal axis 86. In some embodiments of the guide tube 100 depictedin FIG. 11C, a single nozzle 64 comprising multiple orifices 66 (e.g.,two orifices for the example shown in FIG. 11C) can be used to providethe jets. In other embodiments, multiple nozzles can be used.

In some embodiments of the handpiece 50, multiple guide tubes 100 (e.g.,two, three, four, or more) can be disposed at the distal end 58 of thehandpiece 50. Each guide tube 100 can propagate one (or more) jets. FIG.11D is a cross-section view that schematically illustrates an embodimenthaving two guide tubes 100 a and 100 b. In the guide tube 100 a, the jetpropagates along the jet axis 80 a, which is substantially coaxial withthe longitudinal channel axis and the longitudinal guide tube axis. Inthe guide tube 100 b, the jet axis 80 b is offset from the longitudinalaxis 86 of the channel 84. In the illustrated embodiment, thecross-sections of the channels 84 a, 84 b and the guide tubes 100 a, 100b are substantially circular. In other embodiments, the cross-sectionsof the channels or guide tubes can be different than illustrated in FIG.11D (e.g., either or both of the guide tubes 100 a, 100 b could beconfigured similar to any of the guide tubes schematically shown inFIGS. 10A-10F or FIGS. 11A-11C). Also, in any embodiment, thecross-sections of the channels or guide tubes can be different from eachother (e.g., the cross-section of the channel 84 a or the guide tube 100a can be different from the cross-section of the channel 84 b or theguide tube 100 b). In the embodiment schematically illustrated in FIG.11D, the guide tubes 100 a, 100 b are disposed next to each other andare in contact. In some embodiments, the guide tubes can be arranged ina closely-packed configuration, whereas in other embodiments, some orall of the guide tubes may be physically spaced from each other.

FIGS. 12A-12E and FIGS. 13A-13E include perspective views (left-handpanel) and side views (right-hand panel) schematically illustratingvarious embodiments of the impingement member 110, which may be used toconvert the liquid jet 60 into the spray 90. The impingement member 110has an impingement surface 114 upon which the liquid jet 60 can impingeduring operation of the jet apparatus. The impingement surface 114 may,but need not, include a substantially flat section 118 that may bedisposed near the center of the impingement member 110 to intercept thejet 60 (see, e.g., FIGS. 12A, 12B, 12E and FIGS. 13A, 13B, and 13E). Theimpingement surface 114 may, but need not, include angled or curvedsections 122 that angle or curve back toward the direction of theoncoming jet 60 (e.g., away from the distal end 104 of the guide tube)and which may help direct some of the jet 60 (or the spray 90) backtowards the proximal end 106 of the opening 120 (see, e.g., the spray 90schematically shown in FIGS. 6A-6C). For example, FIG. 12A (right-handpanel) schematically shows the jet 60 impinging on the substantiallyflat section 118 of the impingement member 110 and liquid (e.g., jets orsprays) flowing in the directions indicated by arrows 82 a. A possibleadvantage of re-directing the liquid back toward the proximal end 106 ofthe opening 120 is that there may be a reduced likelihood thatpressurized liquid (e.g., jet or spray) enters the canal spaces 30.Although FIGS. 12A and 13A schematically examples of use in which thespray 90 is directed toward the proximal end 106 of the opening 120(see, e.g., the arrows 82 a, 82 b), the impingement surface 114 may beconfigured to direct the spray away from the proximal end 106 of theopening 120. For example, in other embodiments, the impingement surfaces114 may have shapes generally similar to the surfaces 114 shown in FIGS.12A-12E and FIGS. 13A-13E but which bulge away from the distal end 104and toward the proximal end 106 of the opening 120 (e.g., portions ofthe surfaces 114 are convex rather than concave). Some such shapes maydirect the jet or spray toward the distal end 104 of the guide tube andmay increase fluid circulation within the pulp chamber 28 or the canalspaces 30.

The impingement surface 114 can have a variety of shapes, some of whichare depicted in the examples schematically shown in FIGS. 12A-12E and13A-13E. The impingement surfaces 114 of the embodiments in FIGS.13A-13E may be generally similar to the corresponding embodiments shownin FIGS. 12A-12E, respectively. The embodiments in FIGS. 13A-13E includean (optional) outer substantially flat surface 126, which may cause there-directed liquid to flow along the directions indicated by arrows 82 bdue to, e.g., the Coanda effect (see, e.g., the right-hand panel of FIG.13A).

In various embodiments, the impingement surface 114 may be substantiallyflat (see, e.g., FIGS. 12E, 13E). The impingement surface 114 mayinclude one or more sections 122 that angle (see, e.g., FIGS. 12A, 12D,13A, 13E) or curve (see, e.g., FIGS. 12B, 12C, 13B, 13C) back toward theoncoming jet 60 (e.g., away from the distal end 104 of the guide tube).In some embodiments, the section 122 is formed at an angle in a rangefrom about 5 degrees to about 45 degrees, from about 10 degrees to about30 degrees, from about 35 to about 60 degrees, about 60 degrees to about80 degrees, or some other range. In some embodiments, the section 122 isformed at an angle such as, e.g., about 40 degrees, about 45 degrees,about 50 degrees, or about 55 degrees. In some embodiments, the curvedsection 122 comprises a portion of a sphere, ovoid, ellipsoid, toroid,conic section, or other curved surface. In FIGS. 12A-12D, and 13A-13D,the impingement surface 114 is concave toward the oncoming jet, but inother embodiments, the impingement surface 114 may be convex (e.g.,portions of the impingement surface 114 could extend away from, ratherthan toward, the distal end 104 of the guide tube). In the embodimentshown in FIG. 13E, the outer substantially flat section 126 is raisedabove the substantially flat section 118. The height of the raisedsection 126 may be selected to deflect the jet spray 90 away from theimpingement surface 114 by a desired amount.

The impingement member 110 may have a cross-sectional shape or size thatis the same as or different from the cross-sectional shape or size,respectively, of the channel 84 or the guide tube 100. For example, invarious embodiments the width of the impingement plate 110 can be larger(or smaller) than the width of the channel 84 or the width of the guidetube 100.

FIGS. 14A and 14B are a perspective view (FIG. 14A) and a top view (FIG.14B) schematically illustrating an embodiment of an impingement member110 comprising blades 131 to assist forming a vortex flow or circulationin the fluid in the tooth during treatment. In this embodiment, threecurved blades 131 are substantially symmetrically disposed around theimpingement member 110. In other embodiments, a different number ofblades 131 can be used (e.g., one, two, four, or more), and the blades130 may be straight or may be shaped or curved differently than shown inFIGS. 14A and 14B. Arrows 132 indicate the direction of the vortex flowor circulation that may be induced, at least in part, by the blades 131,which in this case is counterclockwise (as seen from the top view inFIG. 14B). In other embodiments, the blades 131 may be configured toproduce a clockwise vortex flow or circulation. In other embodiments,additionally or alternatively to the blades 130, the impingement surface114 may include grooves, ridges, or other features to induce vorticityor circulation, or to otherwise modify the liquid flow or jet spray. Insome treatment methods, the distal end 104 of the guide tube 100 can bepositioned off-center in the tooth 10 to assist forming fluidcirculation or vorticity.

FIGS. 15A-15C are side views of embodiments of impingement members 110that include flexible portions 136 to assist inducing circulation intothe fluid in the tooth 10 during treatment. The flexible portions 136may be relatively thin so that the portions 136 can flex (as shown byarrows 138) as the jet impinges on the impingement surface 114 and fluidflows across the flexible portions 136. For example, it is believed,although not required, that the jet entrains fluid as it propagatestoward the impingement surface 114 and, due to the variable nature ofthe fluid entrainment, the jet may not impinge at precisely the samelocation over time (e.g., the impingement point may oscillate across theimpingement surface 114). Therefore, the fluid flow past the flexibleportions 136 may also be variable, vibratory, or oscillatory, and theflexible portions 136 may adjust their shapes and positions in responseto the resulting variable fluid forces. Flexure, vibration, or motion ofthe flexible portions 136 therefore may aid the impingement member 110in generating fluid circulation or fluid agitation near the distal end104 of the guide tube 100. In some embodiments, the flexible portions136 can be formed by laser machining, wire EDM cutting, or injectionmolding. In the embodiment shown in FIG. 15C, the flexible portions 136comprise a flexible material (e.g., an elastomer) that can be attachedor bonded to the impingement member 110.

FIGS. 16A and 16B are side views that schematically illustrate furtherembodiments of the guide tube 100, which may assist in forming avariable fluid circulation near the distal end 104 of the guide tube. Asdiscussed above, variable entrainment of fluid can cause the liquid jet60 to oscillate slightly as it propagates near the distal end 104 of theguide tube 100. In the embodiment shown in FIG. 16A, a plate 140 mountedon fulcrum 144 (e.g., via a ball-and-socket hinge) can oscillate indirections indicated by arrows 142 as the liquid jet 60 variablyimpinges on the plate 140. In the embodiment shown in FIG. 16B, a ball148 having a diameter slightly less than the diameter of the channel 84is disposed on the impingement member 110. The ball 148 can oscillateand alter the direction and characteristics of the spray 90 produced byimpingement of the jet 60 onto the surface of the ball 148.

FIGS. 17A-17D schematically illustrate embodiments of an impingementmember 110 comprising a permeable material. FIG. 17A is a side viewalong the line A-A shown in FIG. 17B. FIG. 17C is a side view along theline C-C shown in FIG. 17D. In the embodiment of the impingement member110 shown in FIGS. 17A and 17B, a region 152 of the impingement member110 on which the jet 60 impinges comprises the permeable material. Thepermeable material may be at least partly permeable to the liquid of thejet 60, which may allow some of the jet liquid to pass through thematerial (schematically illustrated by arrows 60 a) and some of the jetliquid to be deflected (schematically illustrated by arrows 60 b). It isbelieved, although not required, that jet liquid 60 a that passesthrough the permeable material may help promote fluid circulation orfluid agitation in the pulp cavity 26 during treatment.

The permeable material may comprise mesh, screen, or a porous material.In some implementations, the permeable material comprises one or morelayers of a woven metallic mesh. In some implementations, the permeablematerial is porous such as, e.g., a machined material comprisingopenings sized smaller than the cross-sectional size of the jet whichact to at least partially inhibit flow of the jet liquid through theporous material. In various embodiments, some or all of the impingementmember 110 may be formed from one or more permeable materials. Forexample, FIGS. 17C and 17D depict an embodiment in which substantiallyall of the impingement member 110 comprises a woven mesh.

FIG. 18 is a perspective view schematically illustrating an embodimentof a guide tube 100 comprising posts 160 disposed near the distal end104 of the guide tube 100. In the embodiment shown in FIG. 18, the guidetube 100 can have three posts 160 associated with three openings 120. Inother embodiments, the guide tube 100 may comprise a different number ofposts (and/or openings), e.g., one, two, four, five, six, or more (see,e.g., FIGS. 19A-19E and 20A-20E). Portions of the guide tube 100 and/orthe posts 160 can be formed by laser cutting, laser welding, metalinjection molding, EDM, or other fabrication techniques. For example, insome fabrication techniques, the openings 120 are laser cut from theguide tube 100, thereby forming the posts 160. The posts 160 may extendsubstantially from the proximal end 106 to the distal end 108 of theopenings 120. The impingement member 110 can be formed separately andattached to the body 130 of the guide tube 100 or can be formedintegrally with the guide tube 100 (e.g., during metal injection moldingof the guide tube).

The size, cross-sectional shape, orientation, and/or angular position ofthe posts 160 can be different than shown in FIG. 18. For example, eachof FIGS. 19A-19E includes a perspective view (upper figure) and across-section view (lower figure), taken along the line 19-19 of theupper figure, schematically illustrating an alternate embodiment of aguide tube 100 comprising posts 160. The posts 160 can havecross-sectional shapes that are circular, polygonal, arcuate,wedge-shaped, etc. In any particular embodiment of the guide tube 100,one (or more) of the posts 160 can be sized, shaped, or orienteddifferently from one (or more) other posts 160. One or more of the posts160 may be curved and/or angled (see, e.g., FIG. 19C) which may helpinduce vorticity or fluid circulation in the fluid surrounding thedistal end 104 of the guide tube 100.

The size, shape, orientation, and/or angular distribution of the posts160 (or the size, shape, orientation, and/or angular distribution of theopenings 120) can be used to, at least in part, control the angulardistribution of the spray 90 produced when the liquid jet 60 impinges onthe impingement plate 110. For example, by suitably configuring theposts 160 and/or the openings 120, the angular distribution of the spray(as viewed from the direction of the liquid jet 60) can be made to havea desired angular pattern, be made to be approximately symmetric (e.g.,having two-, three-, four-, or higher-order rotational symmetry aboutthe jet axis), be made to be non-symmetric, or be made to have someother angular distribution about the jet axis.

FIGS. 20A-20E are top views that schematically illustrate some possibleexamples of distributions of the spray 90 that can be produced byvarious embodiments of guide tubes comprising posts 160 and/or openings120. In certain implementations, the spray 90 can exit the guide tube100 through the opening(s) 120, or, alternatively, be thought of asbeing substantially blocked by the posts 160. A desired angular width ofthe spray 90 can be selected by suitably selecting the angular size ofthe post(s) 160 (and/or the opening(s) 120). For example, the angularwidth of the spray may be about 360 degrees to provide spray tosubstantially all regions surrounding the distal end 58 of the guidetube 100. In other embodiments, the angular width of a spray may beabout 270 degrees, about 180 degrees, about 120 degrees, about 90degrees, about 60 degrees, about 45 degrees, about 30 degrees, about 20degrees, or about 10 degrees. Sprays having relatively narrow angularwidths (e.g., about 10 degrees to about 30 degrees) may be used todirect energy of the jet or spray toward a desired location in or near atooth. In various embodiments, the angular width of a spray may be in arange from about 30 degrees to about 60 degrees, about 45 degrees toabout 90 degrees, about 100 degrees to about 145 degrees, about 120degrees to about 240 degrees, or some other range.

In FIGS. 20A-20E, spray is schematically represented byoutwardly-pointing arrows. FIG. 20A schematically illustrates one post160 and one opening 120, with the spray 90 being directed through theopening 120 substantially toward one side of the guide tube 100 (e.g.,toward the top of FIG. 20A). FIG. 20B schematically illustrates twoposts 160 a, 160 b and two openings 120 a, 120 b that are spaced about180 degrees apart to provide a spray 90 having two-fold rotationalsymmetry about the jet (or guide tube or channel) axis. FIGS. 20C and20D schematically three posts 160 a-160 c and three openings 120 a-120c. In FIG. 20C, the posts 160 a-160 c and the openings 120 a-120 c arespaced substantially symmetrically to produce a spray havingsubstantially three-fold rotational symmetry. In FIG. 20D, the posts 160a, 160 b are positioned closer to the post 160 c (e.g., the angularwidth of the opening 120 a is larger than the angular widths of theopenings 120 b, 120 c) so that more of the liquid is deflected to thespray 90 a than the sprays 90 b, 90 c. In FIG. 20E, four posts 160 a-160d and four openings 120 a-120 d are used to provide a spray 90 a-90 dhaving substantially four-fold rotational symmetry. In otherembodiments, the post(s) 160 and/or the opening(s) 120 can be configureddifferently than shown in FIGS. 20A-20E to produce a spray 90 havingdesired characteristics.

In many of the guide tube embodiments described herein, the impingementmember 110 can be oriented approximately perpendicularly with respect tothe longitudinal axis 80 along which the jet 60 propagates (or to thelongitudinal axis 86 of the channel 84 or the longitudinal axis of theguide tube 100). In other embodiments, the impingement member 110 can beoriented at an angle that is non-perpendicular with respect to thelongitudinal axis 80 along which the jet 60 propagates (or to thelongitudinal axis 86 of the channel 84 or the longitudinal axis of theguide tube 100). For example, FIG. 21A is a side view that shows anembodiment of a guide tube 100 having an impingement member 110 that isnot oriented perpendicular to the axis 80 of the liquid jet 60 (which inthis example propagates along the channel axis 86 and the guide tubeaxis). Any of the embodiments of impingement members 110 describedherein (including, but not limited to, the impingement members shown inFIGS. 12A-17D) can be oriented non-perpendicularly to the jet, channel,or guide tube axis. The orientation of the impingement member 110 may beused to direct or deflect the spray toward desired locations (e.g., awayfrom canal spaces during treatment) or to assist providing a desiredfluid circulation or agitation in the tooth during treatment.

FIG. 21B is a side view that schematically illustrates an angle θ thatmay be used to describe an orientation of the impingement member 110with respect to the guide tube 100. In FIG. 21B, the angle θ is definedbetween the jet axis 80, the channel axis 86, or the guide tube axis(not labeled in FIG. 21B, but collinear with the channel axis 86 in thisexample) and a normal 180 to the impingement member 110. For guide tubes100 in which the angle θ is about zero degrees, the impingement member110 is approximately perpendicular to the jet, channel, or guide tubeaxis, as appropriate. In the example shown in FIG. 21B, the angle θ ispositive when the impingement member 110 is angled away from theproximal end 106 of the opening 120 (e.g., angled downward as shown inFIG. 21B), and the angle θ is negative when the impingement member 110is angled toward the proximal end 106 of the opening 120 (e.g., upwardin FIG. 21B). When the angle θ is positive, the spray 90 will tend to bedeflected away from the distal end 104 of the guide tube 100 (see, e.g.,the example schematically shown in FIG. 21A). When the angle θ isnegative, the spray 90 will tend to be deflected toward the distal end104 of the guide tube 100. In various embodiments, either positivevalues or negative values of the angle θ may be utilized to tend todirect the spray 90 away from or toward, respectively, the distal end104 of the guide tube 100. The absolute magnitude of the angle θ may beabout 0 degrees, about 10 degrees, about 20 degrees, about 30 degrees,about 45 degrees, about 50 degrees, about 60 degrees, about 70 degrees,or about 80 degrees. In various embodiments, the absolute magnitude ofthe angle θ may be in a range from about 0 degrees to about 80 degrees,about 20 degrees to about 60 degrees, about 30 degrees to about 50degrees, or some other range. In some embodiments, the angle θ can beadjustable by an operator and may be set or changed to a desired angleprior to (or during) dental treatment.

FIG. 21C is a side view that shows an embodiment of a guide tube 100comprising a curved impingement member 110. In this example, theimpingement member 110 is shaped as an arcuate flap that extends awayfrom the proximal end 106 of the opening 120. The curvature of theimpingement member 110 may be selected to provide a desired direction ordistribution of the spray 90. In some embodiments, two, three, four ormore curved impingement members can be used.

FIGS. 22A-22C are cross-section views schematically illustratingembodiments of handpieces 50 comprising nozzles 64 that are not orientedperpendicular to the axis 86 of the channel 84 in the guide tube 100 orthe axis of the guide tube 100. In FIGS. 22A-22C, the nozzle 64 isdisposed toward the distal end 58 of the guide tube 100. The nozzle 64can be angled such that the liquid jet 60 emitted from the orifice 66 ofthe nozzle 64 propagates along a jet axis 80 that forms an angle withrespect to the longitudinal axis 86 of the channel 84. The angle may beabout 0 degrees (e.g., the jet 60 is emitted substantially along thechannel axis 86), about 10 degrees, about 20 degrees, about 30 degrees,about 45 degrees, about 50 degrees, about 60 degrees, about 70 degrees,about 80 degrees, or about 90 degrees. In various embodiments, the anglemay be in a range from about 0 degrees to about 80 degrees, about 20degrees to about 60 degrees, about 30 degrees to about 50 degrees, about50 degrees to about 90 degrees, or some other range. In someembodiments, the angle can be adjustable by an operator and may be setor changed to a desired angle prior to (or during) dental treatment. Insome embodiments, the guide tube 100 comprises an opening through whichthe jet 60 from the nozzle 64 exits the guide tube. In some embodiments,the nozzle 64 (or multiple nozzles or orifices) may be formed in or on aside wall of the guide tube 100. In some such embodiments, one (or more)jets, beams, or sprays may be delivered from such nozzles or openings.In some such cases, the jets, beams, or sprays are delivered at anglesthat are approximately perpendicular to the longitudinal axis of theguide tube 100 or channel 84. In other such cases, one or more nozzles64 or orifices 66 in the side wall of the guide tube 100 can be orientedtoward the distal end 104 of the guide tube 100 (e.g., to direct thejet, beam, or spray toward the distal end 104) and/or can be orientedtoward the proximal end 102 of the guide tube 100 (e.g., to direct thejet, beam, or spray toward the proximal end 102).

In the embodiment shown in FIG. 22A, the impingement member 110comprises an outer tube 100 a that is disposed around a distal end of aninner tube 100 b. As the jet 60 exits the angled nozzle 64, the jet 60impacts an inner surface of the outer tube 100 a and is deflected intothe spray 90. In the embodiments shown in FIGS. 22B and 22C, theimpingement member 110 comprises one or more flaps, plates, orstructures 110 a, 110 b upon which the jet 60 can impinge and bedeflected into the spray 90. The size, shape, orientation, and/orarrangement of the flaps, plates, or structures can be selected toprovide a desired direction or distribution of the spray 90.

FIG. 23 schematically illustrates an embodiment of a handpiece 50comprising a liquid flow tube 200 configured to provide a stream ofliquid to a tooth location. FIG. 23 is a partial cutaway view in whichthe flow tube 200 is cutaway to show the guide tube 100 disposed in theflow tube. In the illustrated embodiment, the flow tube 200 is disposedaround the guide tube 100, and the stream of liquid flows in a channel204 between an outer surface 208 of the guide tube 100 and an innersurface 206 of the flow tube 200. The stream of liquid may increase theamount of fluid or induce additional circulation in the pulp cavity 26during treatment. The stream of liquid may also reduce or preventintroduction of air into the pulp cavity 26 during treatment. The liquidprovided by the flow tube 200 may, but need not, be different from theliquid used for the jet 60. The handpiece 50 may be configured so thatan operator can provide the stream of liquid from the flow tube 200additionally or alternatively to the jet 60. In some treatments, theflow tube 200 can be used to provide an antiseptic or antibioticsolution (e.g., a bleach such as sodium hypochlorite), a solution withchemicals or medications, or some other liquid. In other embodiments,the flow tube 200 can be disposed adjacent the guide tube 100 ormultiple flow tubes 200 can be used. In some embodiments, additionallyor alternatively to the flow tube 200, a stream of liquid can beprovided along the channel 84 of the guide tube 100.

FIGS. 24A-24F are cross-section views schematically illustratingembodiments of guide tubes 100 having a variety of configurations at thedistal end 104 of the guide tube 100. FIGS. 24A and 24B schematicallyillustrate guide tube embodiments in which the distance between theimpingement surface 114 and a distal-most surface 114 a of the of theimpingement member 110 is different. This distance can act to separatethe impingement surface 114 from the floor of the pulp chamber 28 or thecanal spaces 30 and may reduce the likelihood that during treatment anoperator will position the impingement surface 114 too close to thefloor or canal spaces. One or more portions of the distal-most surface114 a (or other surfaces near the distal end 104) may be substantiallyflat (see, e.g., FIGS. 22A-22B), curved (e.g., partially spherical orelliptical; see, e.g., FIG. 22E), conical or pyramidal (see, e.g., FIGS.22D, 22F), or textured, roughened, or irregular (see, e.g., FIG. 22C).The distal-most surface 114 a may include a tip 116 (see, e.g., FIGS.22D, 22E), which may be rounded or sharp. Texturing or a tip on thesurface 114 a may assist the operator in positioning the distal end 104of the guide tube 100 at or near a desired location in or on a tooth.

In some implementations, the impingement surface 114 (or other surfacesof the guide tube) may be coated with one or more substances thatresists degradation of the surface 114 under the influence of, e.g.,fluid stresses from impingement of the jet 60, cavitation near thedistal end 104 of the guide tube 100, and so forth. In some suchimplementations, the impingement member 110 can be formed from amaterial that is relatively easy to shape, machine, mold, or form butwhich may tend to wear under the impingement stresses or cavitation. Thecoating may advantageously protect such material. One or more coatingsmay be applied to the impingement surface 114 a (or other surfaces ofthe guide tube). Methods including, e.g., plating, chemical solutiondeposition (CSD), chemical vapor deposition (CVD), plasma enhanced CVD,sputtering, pulsed laser deposition, cathodic arc deposition (arc-PVC),or physical vapor deposition (PVD) can be used to form the coating(s).

In some embodiments, the coating can be about 1 to about 7 micron thick,and in some instances (e.g., PVD), may comprise different alloysdepending on the amount of wear resistance desired. For example, thealloys may include titanium nitride (TiN), titanium carbon nitride(TiCN), titanium aluminum nitride (TiAlN), aluminum titanium nitride(AlTiN), titanium aluminum silicon nitride (TiAlSiN), zirconium nitride(ZrN), chromium nitride (CrN), or aluminum chromium nitride (AlCrN).Coatings can include materials such as nickel titanium (NiTi) ordiamond. In some cases, a coating comprising one or more of these alloysmay be able to increase the surface hardness of the impingement surfaceto be in a range from about 1500 HV to about 3500 HV (HV is the Vickerspyramid number) in hardness on the Vickers scale. In other cases thecoating may have a hardness in a range from about 500 HV to about 1000HV, from about 1000 HV to about 4000 HV, or some other range.

In one implementation, the impingement member 110 and the impingementsurface 114 are machined and laser manufactured out of 301 stainlesssteel in the full hard condition (e.g., with a hardness of about 44 HRCon the Rockwell scale, which is approximately 434 HV on the Vickersscale). The impingement surface 114 is then coated with a 1.5 micronthick layer of AlTiN via PVD. In various embodiments, some or all of theguide tube 100 can be formed from stainless steel (e.g., austenitic or300 series stainless steel, ferritic or martensitic stainless steel),carbon steel, titanium, or nickel. In some embodiments, the guide tube100 is formed from INCONEL® available from Special Metals Corporation,New Hartford, N.Y., for example, INCONEL 625 or INCONEL 750 X. Furtherexamples of materials that can be used for embodiments of the guide tube100 include, but are not limited to, Zirconia YTZB, cobalt alloys suchas, e.g., CoCrWNi or CoCrMo MP35N, stellite alloys such as, e.g.,STELLITE® 33 available from Deloro Stellite, Goshen, Ind., HASTELLOY®alloys available from Haynes International, Inc., Kokomo, Ind.,graphene, diamond, silicon nitride, nano-particulated stainless steels,nanocrystalline alloys such as, e.g., NANOVATE®, available fromIntegran, Pittsburgh, Pa., ceramics, and so forth. In some embodiments,other materials may be used such as, for example, rigid polymericmaterials, carbon nanotubes, boron fiber composite tubes, tungsten fibercomposite tubes, etc. In some implementations, the material can comprisefibers embedded in rigid polymeric materials and/or metals. Othermaterials include metal-matrix composites and/or ceramic-metalcomposites. In some embodiments, different portions of the guide tube100 are formed from different materials and/or from combinations of anyof the above materials.

FIG. 25 schematically illustrates use of a handpiece 50 during a dentaltreatment such as, e.g., a root canal procedure. A drill or grindingtool can initially be used to make an opening (not shown in FIG. 25) inthe tooth 10. The opening may extend through the enamel 22 and thedentin 20 to expose and provide access to pulp in the pulp cavity 26.The opening may be made in a top portion of the crown 12 of the tooth 10or in another portion such as a side of the crown 12 or in the root 16below the gum 14. The opening may be sized and shaped as needed toprovide suitable access to the diseased pulp and/or some or all of thecanal spaces 30. The handpiece 50 may be used to deliver a jet 60 ofliquid to a portion of the tooth 10 such as, e.g., the pulp cavity 26.The jet 60 advantageously may, but need not, be a CC jet. In sometreatment methods, the operator can maneuver the handpiece 50 to directthe jet 60 (or the spray 90) around the pulp chamber 28, if desiredduring the treatment process.

The handpiece 50 may comprise any of the embodiments of the handpieces50 described herein. The handpiece 50 may comprise any of the guidetubes 100 or other structures, elements, or features described herein(e.g., the impingement member 100, the opening 120, the flow tube 200,etc.) in any suitable combination. As some non-limiting examples, any ofthe embodiments of the handpieces 50 shown and described with referenceto FIG. 3, 4, 4A, 6, 7A-7B, 9A-9C, 21A-21B, 22A-22C, 23, or 25 can beused with any of the embodiments of the guide tubes 100 shown anddescribed with reference to the foregoing figures and/or to FIGS. 8A-8C,10A-10F, 11A-11D, 16A-16B, 18, 19A-19E, and/or 24A-24F. Also, any of theembodiments of the guide tubes 100 described with reference to theforegoing figures may utilize the impingement members 110 shown anddescribed with reference to the foregoing figures and/or to FIGS.12A-12E, 13A-13E, 14A-14B, 15A-15C, 17A-17D, and/or 20A-20E.

The handpiece 50 can be positioned by an operator so that the distal end104 of the guide tube 100 is disposed at a desired location in, on, ornear the tooth 10 or a tooth surface (e.g., a dentinal surface). Forexample, the distal end 104 of the guide tube 100 may be disposed in thepulp cavity 26 of the tooth. The handpiece 50 can be used to provide ahigh-velocity liquid beam (e.g., a CC jet in some treatments) that maygenerate a pressure wave that can propagate through the tooth 10 or rootcanal system 30 and can detach organic material from the tooth 10 ordentinal surfaces. The liquid beam and/or the pressure wave may cause orincrease the efficacy of various effects that may occur in the toothincluding, but not limited to, acoustic cavitation (e.g., bubbleformation and collapse, microjet formation), fluid agitation, fluidcirculation, sonoporation, sonochemistry, and so forth. In sometreatment methods, submersing the distal end 104 of the guide tube 100in fluid in the tooth 10 under treatment may increase the efficacy ofsome or all of the foregoing effects, which may lead to effectivecleaning of the root canal spaces 30. In certain treatment methods, thenozzle 64 may be disposed toward the distal end 104 of the guide tube100 so that the orifice 66 of the nozzle 64 is submersed in fluid in thetooth under treatment. In certain such embodiments, the liquid jetemerging from the orifice 66 is delivered in a fluid, rather than air,environment and may, in some cases, provide an acoustic field that maybe larger than an acoustic field obtainable from a liquid jet formed inan air environment that subsequently impacts fluid in the tooth.

Optionally, a flow restrictor 210 can be disposed at the distal end 58of the handpiece 50. In some treatment methods, the flow restrictor 210can be used to inhibit backflow of fluid from the tooth under treatment.For example, the flow restrictor 210 may inhibit backflow of fluid outof an opening in the tooth 10. The flow restrictor 210 can besubstantially cylindrical and can substantially surround the guide tube100. The flow restrictor 210 may be configured to contact a portion ofthe tooth 10 during the dental treatment. In some cases, the flowrestrictor 210 is disposed loosely around the guide tube 100. The flowrestrictor 210 may be removably attached to the guide tube 100 in somecases. The flow restrictor 210 can be configured to conform to the crownof the tooth 30 under treatment. The flow restrictor 210 may help tocontain fluid or reduce or inhibit backflow of liquid that emanates fromthe distal end 104 of the guide tube 100 (e.g., jet or spray from theopening 120), liquid that is delivered into the tooth from a flow tube200 (if used), fluid within the pulp cavity, and so forth. The flowrestrictor 210 can be configured such that jet or spray that emergesfrom the opening 120 (or liquid from other sources such as, e.g., theflow tube 200) is sufficiently retained within the pulp cavity 26 sothat the distal end 104 of the guide tube 100 may be contained orsubmersed in the fluid. The opening 120 of the guide tube 100 can becontained or submersed in fluid in the tooth 10. For example, both theproximal end 106 and the distal end 108 of the opening 120 can becontained in fluid in the tooth, e.g., for a lower tooth 10, both theproximal end 106 and the distal end 108 of the opening 120 can besubmersed below the level of fluid in the tooth. In some treatmentmethods, the guide tube 100 may be disposed in a tooth cavity such thatonly a portion of the opening 120 is contained within fluid (e.g., oneof the proximal end 106 or the distal end 108 is contained in fluid). Itis believed (although not required) that treatment methods utilizing aflow restrictor 219 may improve the opportunities for cavitation andpressures waves to be formed in the tooth 30. The flow restrictor 210can be configured such that the liquid emerging from the opening 120 ofthe guide tube 100 is not substantially impeded by the flow restrictor210. For example, the distal surface of the flow restrictor 210 may notextend to or beyond the proximal end 106 of the opening 120. In sometreatment methods, the flow restrictor 210 is applied to the tooth 10,and the handpiece 50 is then maneuvered into position near the tooth 10.

In certain treatment methods, the flow restrictor 210 may, but does notneed to, substantially seal the opening to a cavity in the tooth 10 suchthat the cavity is substantially water tight. For example, in certaintreatment methods, the flow restrictor 210 inhibits back flow of fluidout of the cavity but need not prevent all fluid outflow from the tooth10. For example, in some treatment methods, one or more openings may beformed in the tooth (e.g., via drilling) to allow some fluid to flow outof the cavity in the tooth 10, and the restrictor 210 can be used toreduce or prevent fluid backflow out of other opening(s) (e.g., acoronal access opening).

In some embodiments, the flow restrictor 210 is formed from a materialthat is not adversely affected by chemicals or irrigation solutions suchas, e.g., sodium hypochlorite, used during root canal procedures. Theflow restrictor 210 may comprise any suitable porous and/or absorbentmaterial (or materials) such as, e.g., a sponge. For example, the flowrestrictor 210 may comprise a porous material (e.g., elastomeric,plastic, rubber, cellulose, fabric, foam, etc.) that can at leastpartially absorb liquid. The flow restrictor material may be deformableand may be capable of deforming to contours of tooth surfaces. In someembodiments, the flow restrictor 210 comprises a material having adensity in a range from about 1 to about 1000 kg/m³, or in a range ofabout 10 to about 100 kg/m³. The flow restrictor 210 can have a tensilestrength in a range from about 1 kPa to about 3000 kPa or in a range ofabout 50 kPa to about 400 kPa. The flow restrictor 210 can have anultimate elongation in a range of about 5% to about 800% or in a rangeof about 50% to about 220%. In some embodiments, the flow restrictor 210comprises cells and can have a visual cell count in a range of about 1to about 250/cm or in a range from about 10 to about 40/cm. Materialused for the foam may comprise an ester or another type of foam.

Although the tooth 10 schematically depicted in some of the figures is amolar, the procedures may be performed on any type of tooth such as anincisor, a canine, a bicuspid, or a molar. Also, the disclosed apparatusand methods are capable of treating root canal spaces having a widerange of morphologies, including highly curved root canal spaces.Moreover, the disclosed apparatus and methods may be applied to humanteeth (including juvenile teeth) and/or on animal teeth.

Reference throughout this specification to “some embodiments” or “anembodiment” means that a particular feature, structure, element, act, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, appearances of the phrases “in someembodiments” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodimentand may refer to one or more of the same or different embodiments.Furthermore, the particular features, structures, elements, acts, orcharacteristics may be combined in any suitable manner, as would beapparent to one of ordinary skill in the art from this disclosure, inone or more embodiments. Further, in various embodiments, features,structures, elements, acts, or characteristics can be combined, merged,rearranged, reordered, or left out altogether. Thus, no single feature,structure, element, act, or characteristic or group of features,structures, elements, acts, or characteristics is necessary or requiredfor each embodiment. All possible combinations and subcombinations areintended to fall within the scope of this disclosure.

As used in this application, the terms “comprising,” “including,”“having,” and the like are synonymous and are used inclusively, in anopen-ended fashion, and do not exclude additional elements, features,acts, operations, and so forth. Also, the term “or” is used in itsinclusive sense (and not in its exclusive sense) so that when used, forexample, to connect a list of elements, the term “or” means one, some,or all of the elements in the list.

Similarly, it should be appreciated that in the above description ofembodiments, various features are sometimes grouped together in a singleembodiment, figure, or description thereof for the purpose ofstreamlining the disclosure and aiding in the understanding of one ormore of the various inventive aspects. This method of disclosure,however, is not to be interpreted as reflecting an intention that anyclaim require more features than are expressly recited in that claim.Rather, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment.

The foregoing description sets forth various example embodiments andother illustrative, but non-limiting, embodiments of the inventionsdisclosed herein. The description provides details regardingcombinations, modes, and uses of the disclosed inventions. Othervariations, combinations, modifications, equivalents, modes, uses,implementations, and/or applications of the disclosed features andaspects of the embodiments are also within the scope of this disclosure,including those that become apparent to those of skill in the art uponreading this specification. Additionally, certain objects and advantagesof the inventions are described herein. It is to be understood that notnecessarily all such objects or advantages may be achieved in anyparticular embodiment. Thus, for example, those skilled in the art willrecognize that the inventions may be embodied or carried out in a mannerthat achieves or optimizes one advantage or group of advantages astaught herein without necessarily achieving other objects or advantagesas may be taught or suggested herein. Also, in any method or processdisclosed herein, the acts or operations making up the method or processmay be performed in any suitable sequence and are not necessarilylimited to any particular disclosed sequence.

1. (canceled)
 2. A dental instrument comprising: a pressure wavegenerator configured to form a liquid jet that creates acoustic energy,the pressure wave generator comprising a positioning member, thepositioning member comprising: a channel or lumen along which or throughwhich the liquid jet can propagate; a distal end portion comprising animpingement surface on which the liquid jet impinges and is deflectedback into jets or spray; and one or more openings proximal of theimpingement surface that permit deflected liquid to exit the positioningmember and interact with a surrounding environment in a tooth.
 3. Thedental instrument of claim 2, further comprising a nozzle configured toform the liquid jet.
 4. The dental instrument of claim 3, wherein thenozzle comprises an orifice configured to provide a coherent, collimatedjet.
 5. The dental instrument of claim 4, wherein the orifice issubstantially circularly symmetric, and preferably formed at an angle toa proximal surface of the nozzle.
 6. The dental instrument of claim 2,wherein the pressure wave generator is configured to generate ahydroacoustic field including acoustic power over a broad range ofacoustic frequencies.
 7. The dental instrument of claim 2, wherein thechannel or lumen comprises a bend.
 8. The dental instrument of claim 2,wherein a cross-section of the channel or lumen changes along alongitudinal axis.
 9. The dental instrument of claim 2, wherein theimpingement surface comprises one or more angled or curved portions. 10.The dental instrument of claim 9, wherein the one or more angled orcurved portions angle or curve back toward a direction of the oncomingjet.
 11. The dental instrument of claim 2, wherein the impingementsurface is configured to direct the jets or spray towards the one ormore openings
 12. The dental instrument of claim 11, wherein theimpingement surface is configured to direct the jets or spray towards aproximal end of the one or more openings.
 13. The dental instrument ofclaim 2, further comprising a flow tube configured to deliver alow-velocity stream of fluid to a cavity in a tooth.
 14. The dentalinstrument of claim 13, wherein the fluid provided by the flow tube isdifferent from the liquid used for the liquid jet.
 15. The dentalinstrument of claim 13, wherein the flow tube is disposed around thepositioning member.
 16. The dental instrument of claim 2, wherein theimpingement surface comprises a protective coating.
 17. A dentalinstrument comprising: a positioning member having a channel configuredto deliver a high-velocity liquid jet to a cavity in a tooth, thepositioning member having a proximal end portion and a distal endportion, the distal end portion configured to deliver liquid into thecavity in the tooth; a backflow restrictor configured to be applied tothe tooth and to inhibit backflow of fluid out of an opening in thetooth during operation of the liquid jet, at least a portion of thebackflow restrictor disposed between the proximal end portion and thedistal end portion of the positioning member; and a flow tube configuredto deliver a low-velocity stream of fluid along with the liquid to thecavity in the tooth.
 18. The dental instrument of claim 17, wherein thefluid provided by the flow tube is different from the liquid used forthe liquid jet.
 19. The dental instrument of claim 17, wherein the flowtube is disposed around the positioning member.
 20. The dentalinstrument of claim 19, wherein the flow tube is configured to deliverthe low-velocity stream of fluid in a channel between an outer surfaceof the positioning member and an inner surface of the flow tube.
 21. Thedental instrument of claim 17, wherein the distal end portion of thepositioning member comprises an impingement surface on which the liquidjet impinges and is deflected back into jets or spray.